Turn your brightness down to a comfortable amount down low.
Turn off unneeded notifications. Go to settings > Notification Centre > Then turn off unneeded notifications for apps
Turn off background app refresh. Go to settings > General > Background app refresh > Off
Do not use Dynamic wallpapers (4s and up). Go to settings > Wallpapers and Brightness > Then use a Static background or one you've saved
Turn off auto fetch for your mail accounts. Go to settings > Mail, Contacts, Calendars > Fetch New Data > Scroll down to "Fetch", and set it to 'manually'
Turn off automatic downloads of music + apps, and updates (new with iOS 7). Go to settings > iTunes and AppStore > Scroll down to automatic downloads and turn all three off
- 1.0 iDevice running iOS 7